effect modifier

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ef·fect mod·i·fi·er

a factor that modifies the effect of a putative causal factor under study; for example, age is an effect modifier for many conditions.


a result produced by an action. The relationship between the two can be expressed in linear form. The total association between them may be the sum of a number of effects. The effect may be direct when it is exerted without being transmitted through intervening factors, or indirect when it is. It may also be a spurious effect when the observed changes are due to causes and correlations common to both.

additive effect
the combined effect produced by the action of two or more agents, being equal to the sum of their separate effects.
Coolidge effect
the stimulation of sexual behavior in a male animal upon exposure to a new female.
cumulative effect
cumulation action.
experimenter e's
demand characteristics; the characteristics supplied by the experimental subject in response to what it perceives are the demands of the experimenter.
effect modifier
a factor which modifies the effect of a causal factor under study. Called also interaction.
position effect
in genetics, the changed effect produced by alteration of the relative positions of various genes on the chromosomes.
pressure effect
the sum of the changes that are due to obstruction of tissue drainage by pressure.
side effect
a consequence other than that for which an agent is used, especially an adverse effect on another organ system.
References in periodicals archive ?
Effect modifiers represent various study and patient characteristics that are also associated with the patient characteristics.
Apart from the primary outcome, in the results we have stratified safety among the age and gender, to see effect modifiers.
The results obtained in the present study do not clarify the role of SES as an effect modifier of the association between mortality and variation in [NO.
We also present the exposure-response curves as shaped for cities with corresponding levels of the presented effect modifier equal to the 25th and the 75th percentile of the distribution of the relevant effect modifier.
To broadly describe the status of this research, we compiled a nonexhaustive list of these exposures and biomarkers or diseases with their potential genetic effect modifiers, shown in Table 1, by searching the published literature (see Appendix 1 for additional information about the genes).
We then subdivided those counts by the presence or absence of the potential effect modifier and reestimated our regressions on those subgroups.
Details on confounders, effect modifiers, sample collections, and calculations of the intra-cluster correlation coefficient are given in the Supplemental Material ("Confounders and effect modifiers" and "Intra-Cluster Correlation Coefficient").
RVR was stratified among age, viral load and gender to see the effect modifiers and result were presented in graphs and tables.
After examining the prevalence of hypoglycemia across potential effect modifiers, however, they found no significant interactions.
Kevin Maki noted, "Meta-analysis can provide misleading results due to a number of factors, including improper procedures for identification of studies, differences in clinical characteristics of subjects across investigations, heterogeneity in study methods and/or results, the presence of unknown confounders or effect modifiers, and publication bias.
The reviewers also complained in their report about the absence of data on treatment effect modifiers.